Hydrocarbon conversion process



Feb. 24, 1959 T. M. ENGLE HYDRocARBoN CONVERSION PRocEss Filed Aug. 19,1953 x OF- 1 3 e 8 SW. W 7 LALML O .7 L 4 FO JNVENTOR. THEoooRE M.EN|GLE BY mf' I 2,875,147 HYDROCARBON CONVERSION PROCESS meedereM.Engle, Pennington, N..J.,assigmrm Hydrocarbon Research,rll1c.,` NewYork, N. Y., a corporation of New Jersey d d d Appliasion Angustia,1953,'stria1No. 315,133

' s claims; `(Cl. 20s-59) This" invention relates to the`high-temperature treatment of `hydrocarbons and is more. particularlyconcelhed' with the efficient production of high octane gasline""fromheavyhydrocarbon oils.

`The `invention is"`particularly` applicable to the conversion of heavycharge stocks which cannot be economically treated by conventionalprocesses. It can elticientlyjconvert reduced ,crudes of high Ramsbottomcarbon residue into `economic yields of high octane gasline. Itcanalsobe used on Vheavy crudes which, on

eating, 'would prlcduc'e a .coke salable only for low Vgrade fuelpurposes by"re'a"son of it's sulfur and/o1"` nitro- 'gen and/rmietalcontent. It can be used on lighter il stocks which contain catalystpoisons such as metals and, therefore, are unsuitable for directcharging to catalytic crackers. 1 d

`Recently proposed proesses suggest .converting hy dr'carboiih oils atelevated pressures and temperatures by contact with `afmassofheatedcontact material in the. presence of hydrogen.,. One suchprocess, described copending application of Finneran et`al.`,l` Serial`No. 299,114, iilediuly 16, 1952', discloses contactingthefhydrocarbonoil with` a A,flliidized `bed ofparticulate contact material, the`particles ofiwhicl'i circulate between the', conversionzone and ahydrogen-producing regen-` Thus, an object-of `the invention is toprovide a dex ible, `high-temperature treating process, by means ofwhich gasoline of high octane number,` high stability and `low sulfurcontent, is=produced from low grade, heavyhydrocarbon oils. i l l `Otherobjects and advantages will be .apparent from the' description whichfollows. A l i i f i `In accordance withthe invention, hydrocarbon "oilis` converted.` Yiii-an elongatedwupow' conversion zone by contact witha `liydrog'en'containing gas and" a particulatef contact material orcarrier withdrawn from a tluidized` bett` r The uidized bed 'fisdividedintofat least` two zones, a reaennsrne (hereinafter called thesecondary con-` version zone) into whichdthe carrier passes aftercontacting, the hydrocarbon oil` in the elongated upow or primary`e`onvesin ione, and-a regeneration zone whereinua regeneratinggas`comprising ,predominant-ly steam and oxygen reacts at temperatures aboveabout 16002" United States Patent G ize-the carrier in the secondaryconversionione imparts.`

21,875,147 Patented Feib. 24, 1959 ice F. with carbonaceous materialdeposited `on the carrier by the hydrocarbon conversion toformhydrogen-containing regeneration product gases; the regeneration productgases pass up" through the bed, iluidizing the carrier particles andaiding the hydrocarbon.` conversion in the secondary conversion zone.

Circulation of carrier between the fluidizcd bed` and the upow orprimary hydrocarbon conversion zone is largely independent ofcirculation within the bed between regeneration zone and secondaryconversion zone. As one result, the optimum carrier-to-oil ratio(.pounds of carrier per pound of charge oil) for the primary hydro@carbon conversion may be set without adverse eiect on regenerationconditions, just as regeneration conditions may be set without adverseelect on the primary hydrocarbon conversion. Then again, freeing theprimary' conversion zone` -from any dependence upon regenerationconditions imparts additional degrees `of flexibility. For example, atany particular `carrier-to-oil'` ratio in the generally employed Vrangeof 1:1 to l5 :1., they zone of primary conversion may vary, e. g., froma dilute gaseous suspension of carrier as low as 0.5 pound per cubicfoot, moving, at a linear velocity as high as 40 `feet` per second, toan upowing denser suspension as high as 10 pounds per cubic foottransported by gas having a velocity as `low as 3 feet per second.Generally; the hydrogen content of the suspending gas is atleast 20% byvolume. The `hydrogen content and total amount of suspending Agas usedin the primary conversion Vzone are also freed from dependenceY on theop,- erating conditions of the regeneration zone. However, theregeneration zone `is thepreferred originalsource foi-the hydrogen.Hydrogen is present in the .gaseous elliuent` `from the secondaryConversion zone as well` as `in thepure regenerationV product gases. Astream of either of `these two gases, after suitable,treatmenttoinjcrease the, `hydrogencontent when desired, w-ill serve well for `thesuspending gas in thefprimary conversion zone.`

`Generally, the primary conversion zoneroperates in= the temperaturerange of #about 800 to 1050* F., prei" erably 850` to 950 `F., with acarrier-tooilrratio in the preferredqrangeof 21:1 to ltlrlandl a`carriertogas ratio in the range of about 2` to 6 pounds `per cubic footof suspending gas at conversion pressure and temperature. Total pressuremay range from V150 to 1000` p. s. i. g. (pounds per square inch gage);hydrogenpartial pressure should be atleast 35 1p. s. i. (pounds per`squareinchf)r,the Vrange of 75 to 400 p. s. i. being preferred:`Withinthese ranges,4 operating conditions in the primary conversion`zone `aregenerally` selected to `achieve maxi` mum production of highoctane gasoline consistent with,

minimum production of 4coke `from the charge oil. To

this end', `completefconversion `of the' hydrocarbons into the ultimateproductsis-lbest not attempted `in `the primary conversion zone.`Rather, an `appreciable portion, of the conversion is performed in the-secondary con-1 maintained at temperatures ranginglfrom -50 tcl-200 Faabove the temperature in the 4primary conversion zoneby directlyreturning freshly regenerated carrier particles from Ythe regenerationzone to the secondaryconversiom zone. Using the-hot 4regenerationproduct gasesttuidadditional heat and, more importantly,prtivideswtheiiy-r `carrier to the secondary conversion zone.

drogen-containing atmosphere so beneficial for the completion of thehydrocarbon conversion. The hydrocarbonaceous deposit formed on thecarrier particles 1n the primary conversion zone is converted intovolatilized products and a non-volatile carbonaceous residue or coke bythe time these particlespass from the secondary conversion zone to theregeneration zone. The secondary conversion zone appears to beparticularly beneficial, when `operated at a hydrogen partial pressurein the range of 35 to 200 p. s. i., in minimizing the quantity ofmaterial that must be removed from the carrier by regeneration.

In the regeneration zone, the coke deposit on the carrier is reactedwith regenerating gas consisting essentially of steam and oxygen at atemperature in the range of y1600 Vto 2500 F., preferably 1700 to 2000"F. The regeneration of the carrier results in the production of agaseous mixture comprising essentially hydrogen, carbon monoxide, carbondioxide and excess steam. The regenerating gas contains a preponderanceof steam and a minor proportion of high-purity oxygen, the latter morespecifically containing at least about 90% by volume of oxygen,preferably at least 95 %.by volume of oxygen, and obtained, for example,by the liquefaction and rectilication of air. Steam-to-oxygen molarratios in the range of 1.5:1 to 5:1 are generally satisfactory forgenerating the desired hydrogen. It is frequently preferable toemploy asteam-to-oxygenmolar ratio of the order of 2:1 to 3:1.

An up-transport zone serves to return hot regenerated In theluptransport zone which is fed with carrier particles from theregeneration zone, the carrier particles ilow upwardly because of the,lower fluid-static head maintained in this zone. The gas velocity in theup-transportv zone is generally in the range'of about 0.5 to 5 feet persecond. The transportgas may be steam or recycled product gas fromwhich, preferably, all hydrocarbons containing more than two carbonatoms have been removed.

The carrier circulation rate is advantageously controlled to ensure thatregeneration does not completely consume the coke deposit on the carrierfor the reason that regeneration at temperatures above 1600" F. withsteam and oxygen activates the carbon left on the carrier. Preferably,the carrier returning through the up-transport zone has about l to 3% byweight of activated carbon. In this fashion, the catalyticpropertiesresiding in activated carbon may be utilized in the hydrocarbonconversion. For example, lowered production of diolens may be attainedthrough the catalytic influence of activated carbon, diolens apparentlybeing readily hydrogenated to more saturated compounds; also, much ofthe sulfur originally present in the hydrocarbon'oil is catalyticallyconverted to hydrogen sulfide. These catalytic properties of activatedcarbon are effectively brought to bear on the hydrocarbonY charge stockthrough the good gas-solids contact achieved by the dilute phaseoperationl of the upow or primary conversion zone.

The particular carrier employed in the process of this invention is anysolid material that will withstand the desired regeneration conditions,including a temperature above 1600'F., without physically disintegratingor fusing, such as sand, quartz, alumina, magnesia, zircon,berylorbauxite.

To describe and explain this invention more fully, reference is made tothe accompanying drawing which shows diagrammatically a vertical sectionof a reactor adapted for carrying out the process of the invention.

In the operation of the apparatus illustrated, a heavy hydrocarbon oil,preferably preheated to about 600 F., is supplied by line and broughtinto contact with hot carrier particles leaving conduit 12.Hydrogen-containing suspending gas from line 14 sends carrier andhydrocarbon oil up'through the conduit forming primary conversion zonevlwherein much of the hydrocarbon oil is 4 f converted into volatilizedproducts and a hydrocarbonaceous deposit on the carrier.

Gas, fouled carrier and volatilized products of the conversion pass fromprimary conversion zone 16 into a cylindrical vessel 18 containingiluidized bed 20 of carrier particles. Bed 20 is Idivided into an uppersecondary conversion zone 22 and a lower regeneration zone 24 by apacked section 26 which is provided by a perforated plate 25 supportinga mass of packing bodies 27, e. g., Raschig rings. Carrier particlesfrom zone 22 move downwardly through packed section 26 in contact withregeneration product gases flowing upwardly from zone 24. The fouledcarrier particles reaching regeneration zone 24 have only a carbonaceousresidue of very low hydrogen content. Primary conversion zone 16discharges suspending gas, carrier and all conversion products directlyinto the upper portion of zone 22 of iluidized' bed 20 but may bearranged to `discharge into the gas-solids disengaging space 19 abovebed 20. All of the gases and volatilized products from both zone 16 andbed 20 pass through cyclone separator 28 and into line 30. u

Zone 22 of uidized bed 20 together with packed section 26 provides thelocus for secondary conversion. In subjacent regeneration zone 24, steamand oxygen supplied by line 32 react with the carbonaceousresidue orcoke deposit on the carrier toA yield regeneration product gasesconsisting essentially of hydrogen, carbon oxides and excess steam whichin uidizing bed 20 provide the hydrogen-containing atmosphere forsecondary conversion. The regeneration incompletely consumes the cokedeposit, leaving activated carbon on the carrier particles.

An upright tube 34 open at its bottom to regeneration zone ,24 and atits top to zone 22 permits the return of regenerated carrier to zone 22by means of a gasiform transport medium injected intoV the base of tubeV34 through the tubular stem 35 of adjustable valve 36. The opening33 intube 34 may be partially or completely closed by suitable verticalmovement of valve 36.

Carrier particles from fluidized bed 20 are passed to primaryconversionzone 16 through conduit 12 which is provided with valve 13 to regulatethe rate of ow of carrier to zone 16.

' The total gasiform effluent passes from reactor 18 by way of separator28 and line 30 to a conventional recovery plant 42 wherein the effluentis separated into nr- While a substantial portion of this product gas isdis-f charged through line 53 for utilization as a fuel or chemical rawmaterial, a portion enters hydrogen concentration plant 54 wherein byknown methods the hydrogen content of the gas is increased from say 20%by volume o Example I' A 25 wt. percent reduced Kuwait crude (8.9 API,

5.3 wt. percent sulfur and 20.2 Wt. percent Ramsbottom;

carbon) is preheated toj500 F. and charged at the rate velocity of aboutfeet'per'seconld. The totalpressure is 400 p. s. i. g. and the hydrogenpartial pressure is about 260 p. s. i.

Steam and high-purity oxygen (95 vol. percent oxygen) enter regenerationzone 24 through line 32 at the rates of 77,000 and 72,000 pounds perhour, respectively. An additional 25,000 pounds per hour of steam fromline 36 transports regenerated carrier up tube 34. The temperature inzone 24 is maintained at 1800D F. and in Zone 22 at about 975 F.

From the gasiform efuent removed through line 30 is recovered 20,000barrels per day of a middle fraction boiling between 400 and 800 F.which is recycled by way of line 44 to zone 22. Also, part of theproduct gas (comprising chiefly hydrogen, carbon monoxide, carbondioxide, methane, ethane and ethylene) passes through line 52 toconcentration plant 54 where it is scrubbed to remove carbon dioxide,then reheated and shifted in the presence of added steam over aniron-chromium catalyst at a temperature of about 750 F. The resultantmixture is again scrubbed to eliminate carbon dioxide and leave a gascontaining about 70 vol. percent hydrogen, 14 vol. percent methane, 7vol. percent ethane and 4 vol. percent ethylene. The hydrogen-rich gasis compressed and passed through line 56 and line 14 to serve as thesuspending gas in primary conversion zone 16.

The ultimate products recovered comprise 13,000 barrels per day of highoctane gasoline (91 CFRR clear), 4600 barrels per day of fuel oilmeeting ASTM specifications for No. 6 fuel oil, 1700 barrels per day ofpropane, and about 79,000,000 standard cubic feet per day of fuel gaswith a heating value of about 490 B. t. u. per standard cubic foot. Thegasoline contains 0.2 wt. percent sulfur and has an oxidation stabilitycorresponding to an ASTM induction time of 7 hours.

Example Il ucts issuing from primary conversion zone 16 may be passeddirectly into a gas-solid separator, the gasiform products removed fortreatment per se and only the solids passed into secondary conversionzone 22. Such arrangement simplies the hydrocarbon product recoverysystem but necessitates duplication of recovery equipment to handleseparately the gasiform eflluent from secondary conversion zone 22.Accordingly, all variations conforming to the spirit of the inventionare to 4be considered within the scope of the appended claims.

What is claimed is:

1. A hydrocarbon conversion process which comprises forming with heatedparticulate carrier a lluidized bed divided into `a lower regenerationzone and an upper secondary conversion zone, withdrawing carrier fromsaid secondary conversion zone, contacting a heavy hydrocarbon oil ofhigh Ramsbottom carbon residue with the withdrawn carrier and with asuspending gas containing at least 20% by volume of hydrogen and passingthe resulting suspension of said oil and carrier in dilute phaseupwardly through an elongated primary conversion zone main- 6 tained `ata temperature inthe range of nabout 180Mo 1050" F. and a pressureintheragef aboit 15'0 tofi100`0 p. s. i-` g`. whereby said oil isconverted'i'nto volatilized products and a hydrocarbonaceous depositfouling said carrier, passing fouled carrier from said` primaryconversion zone into said secondary conversonzone andtherein converting`said hydrocarbonaceous deposit into coke of low hydrogen content bycontact with hydrogen-contain# ing regeneration product gases at atemperature about 50 to 200 F. above the temperature of said primaryconversion zone, withdrawing said volatilized products for recoverywhile limiting the contact thereof with said fluidized bed to not morethan the upper end portion of said secondary conversion zone,regenerating carrier in said regeneration zone by reacting the cokethereon with steam and oxygen at a temperature in the range of 1600 to2500 F. to form said regeneration product gases, separating from saidregeneration product gases said hydrogen-containing suspending gas, andcirculating said .carrier in said fluidized bed between said secondaryconversion zone and said regeneration zone.

2. The process of claim 1 wherein the carrier, hydrocarbon oil andhydrogen-containing suspending gas traverse said primary conversion zoneas a dilute phase suspension containing about 2 to 6 pounds of carrierper cubic foot of suspending gas.

3. The process of claim 1 wherein the hydrogen in said primaryconversion zone exerts a partial pressure in the range of about 75 to400 p. s. i.

4. A process for the conversion of 'a heavy hydrocarbon oil of highRamsbottom carbon residue which comprises forming with heatedparticulate carrier a lluidized bed divided into a lower regenerationzone and an upper secondary conversion zone, withdrawing carrier fromsaid secondary conversion zone, contacting said oi-l with the withdrawncarrier `and with a suspending gas containing at least about 20% byvolume of hydrogen and passing the resulting suspension of said oil andcarrier in dilute phase upwardly through an elongated primary conversionzone maintained at a temperature in the range of about 850 to 950 F. anda pressure in the range of about 150 to 1000 p. s. i. g. whereby saidoil is converted into volatilized products and a. hydrocarbonaceousdeposit fouling said carrier, passing fouled carrier from said primaryconversion zone into the upper portion of said secondary conversionzone, said upper portion being at a temperature about 50 to 200 F. abovethe temperature of said primary conversion zone and the lower portion ofsaid secondary conversion zone having a vertical gradient of increasingtemperature approaching the temperature of said regeneration zone wheresaid lower portion is contiguous to said regeneration zone, withdrawingsaid volatilized products for recovery while limiting the contactthereof with said fluidized bed to not more than the upper end portionof said secondary conversion zone, converting said hydrocarbonaceousdeposit into coke of low hydrogen content by contact withhydrogen-containing regeneration product gases while passing said fouledcarrier downwardly through said secondary conversion zone to saidregeneration zone, regenerating carrier in said regeneration zone byreacting the coke thereon with steam and oxygen at a temperature in therange of about 1700 to 2000 F. to form said regeneration product gases,separating from said regeneration product gases said suspending gas, andcirculating said carrier in said luidized bed from said upper portionthrough said lower portion to said regeneration zone and thence to saidupper portion.

5. The process of claim 4 wherein the carrier, heavy hydrocarbon oil andsuspending gas traverse said primary conversion zone as a suspensionhaving a. velocity of at least 3 feet per second and containing not morethan 10 pounds of carrier per cubic foot of suspending gas.

6. The process of claim 4 wherein heavy hydrocarbons recovered from thevolatilized products are injected into said secondary conversion zone`at a level substantially below the level of entry of said fouledcarrier frornsaid primary conversion zone. y 1 7. The process of claim 4wherein the hydrogen in said primary conversion zone exerts a partialpressure in the range of about 75 to 400 p. s. i.

8. The process of claim 7 wherein the hydrogen in saidsecondaryeonversion zone exerts a partial pressure in the range of about35 to 200 p. s. i.

References Cited in the le of this patent NITBD STATES PATENTS u 1Keith1July 20, 1948 Guyer oct. 5, 194s Gom May 24, 1949 0de11 June 19,` 1951 nBekberger Mar. 13,1956

1. A HYDROCARBON CONVERSION PROCESS WHICH COMPRISES FORMING WITH HEATEDPARTICULATE CARRIER A FLUIDIZED BED DIVIDED INTO A LOWER REGENERATIONZONE AND AN UPPER SECONDARY CONVERSION ZONE, WITHDRAWING CARRIER FROMSAID SECONDARY CONVERSION ZONE, CONTACTING A HEAVY HYDROCARBON OIL OFHIGH RAMSBOTTOM CARBON RESIDUE WITH THE WITHDRAWN CARRIER AND WITH ASUSPENDING GAS CONTAINING AT LEAST 20% BY VOLUME OF HYDROGEN AND PASSINGTHE RESULTING SUSPENSION OF SAID OIL AND CARRIER IN DILUTE PHASEUPWARDLY THROUGH AN ELONGATED PRIMARY CONVERSION ZONE MAINTAINED AT ATEMPERATURE IN THE RANGE OF ABOUT 800 TO 1050*F. AND A PRESSURE IN THERANGE OF ABOUT 150 TO 1000 P. S. I. G. WHEREBY SAID OIL IS CONVERTEDINTO VOLATIZED PRODUCTS AND A HYDROCARBONACEOUS DEPOSIT FOULING SAIDCARRIER, PASSING FOULED CARRIER FROM SAID PRIMARY CONVERSION ZONE INTOSAID SECONDARY CONVERSION ZONE AND THEREIN CONVERTING SAIDHYDROCARBONACEOUS DEPOSIT INTO COKE OF LOW HYDROGEN CONTENT BY CONTACTWITH HYDROGEN-CONTAINING REGENERATION PRODUCT GASES AT A TEMPERATUREABOUT 50 TO 200*F. ABOVE THE TEMPERATURE OF SAID PRIMARY CONVERSIONZONE, WITHDRAWING SAID VOLATILIZED PRODUCTS FOR RECOVERY WHILE LIMITINGTHE CONTACT THEREOF WITH SAID FLUIDIZED BED TO NOT MORE THAN THE UPPEREND PORTION OF SAID SECONDARY CONVERSION ZONE, REGENERATING CARRIER INSAID REGENERATING ZONE BY REACTING THE COKE THEREON WITH STREAM ANDOXYGEN AT A TEMPERATURE IN THE RANGE OF 1600 TO 2500*F. TO FORM SAIDREGENERATION PRODUCT GASES, SEPA-